Plant virus disease is an important factor restricting the safe production of crops. Virus detection can identify viruses and determine the types of viruses, which is the key to disease monitoring, early warning and prevention in crops production. In this study, a detection system based on Recombinase Polymerase Amplification-Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated 12a (RPA-CRISPR/Cas12a) was established for potato virus Y (PVY). The results showed that: (1) Cas12a and other components in the CRISPR/Cas12a detection system were necessary for the detection; (2) The target location of crRNA had a significant effect on Cas12a nuclease activity, and the reaction efficiency was the highest when the target of crRNA contained part of PAM site sequence; (3) The minimum detection limit of RPA-CRISPR/Cas12a was 3×10² copies∙μL^-1, which was higher than that of PCR and qPCR methods; (4) The combination of RPA-CRISPR/Cas12a system with crude extraction of nucleic acid and reverse transcription could detect PVY in a non-laboratory setting and the whole process took about 60 minutes. The RPA-CRISPR/Cas12a detection system of PVY established in this study provides an effective method for real-time and rapid visual detection of plant viruses under non-laboratory conditions.